var xOp7Up,xOp6Dn,xIE4Up,xIE4,xIE5,xNN4,xUA=navigator.userAgent.toLowerCase();

if(window.opera)
{
	var i=xUA.indexOf('opera');
	if(i!=-1)
	{
		var v=parseInt(xUA.charAt(i+6));
		xOp7Up=v>=7;
		xOp6Dn=v<7;
	}
}
else if(navigator.vendor!='KDE' && document.all && xUA.indexOf('msie')!=-1)
{
	xIE4Up=parseFloat(navigator.appVersion)>=4;
	xIE4=xUA.indexOf('msie 4')!=-1;
	xIE5=xUA.indexOf('msie 5')!=-1;
}
else if(document.layers)
{	
	xNN4=true;
}
xMac=xUA.indexOf('mac')!=-1;
function xDef()
{
	for(var i=0; i<arguments.length; ++i)
	{
		if(typeof(arguments[i])=='undefined') 
			return false;
	}
	return true;
}
function xDisplay(e,s)
{
	if(!(e=xGetElementById(e))) 
		return null;
	if(e.style && xDef(e.style.display)) 
	{
		if (xStr(s)) 
			e.style.display = s;
		return e.style.display;
	}
	return null;
}

function xGetElementById(e)
{
	if(typeof(e)=='string') 
	{
		if(document.getElementById) 
			e=document.getElementById(e);
		else if(document.all) 
			e=document.all[e];
		else 
			e=null;
	}
	return e;
}

function xHide(e)
{
	return xVisibility(e,0);
}

function xShow(e) 
{
	return xVisibility(e,1);
}
function xStr(s)
{
	for(var i=0; i<arguments.length; ++i)
	{
		if(typeof(arguments[i])!='string') 
			return false;
	}
	return true;
}

function xVisibility(e, bShow)
{
	if(!(e=xGetElementById(e))) 
		return null;
	if(e.style && xDef(e.style.visibility)) 
	{	
		if (xDef(bShow)) e.style.visibility = bShow ? 'visible' : 'hidden';
		return e.style.visibility;
	}
	return null;
}